Relaxation time versus molecular volume

Figure 1.1 A plot of relaxation times versus molecular volume for a series of closely related alcohols demonstrating the overall validity of the Debye equation. The outlying point refers to benzyl alcohol (see text for further discussion).

This equation is equivalent to Eq. [1053], except for the use of polarization in place of anisotropy. When using this equation, one plots (l/P- ) versus 77r] to obtain the molecular volume (Figure 10.13, lower panel). The intercept yields an apparent value of (I/P8 -1), which can be larger than the true value (l/Po - if there is segmental motion of the pobe. The term p is die rotational relaxation time (p = 36). At present, the use of anisotropy, the rota-tional correlation time, and Eq. [10.53] is preferred. 

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